1. Field of the Invention
The present invention relates to an LED (Light Emitting Diode) package used as a light source for a backlight assembly for an LCD, and a backlight assembly for an LCD comprising the same. More particularly, the present invention relates to an LED package having improved uniformity in luminance and color of light so as to be used as a light source for a backlight assembly, and a backlight assembly for an LCD comprising the same.
2. Description of the Related Art
Generally, LCDs (Liquid Crystal Displays) are passive optical elements, which cannot emit light by itself, and thus displaying images using a backlight assembly attached to a rear surface of an LCD panel. Recent backlight assemblies having various structures have been developed to satisfy slim and lightweight trends for assuring competitiveness of obtained products. Particularly, the LCDs are mainly used in notebook computers and wall-mounted large TVs, thus being required to satisfy the slim and lightweight trends.
A cold cathode fluorescent lamp (hereinafter, referred to as a “CCFL”) was used as a conventional light source for generating light for the above backlight assemblies, but is now being replaced with an LED having a high luminance so as to meet the slim and lightweight trends. While the conventional CCFL is a line light source for emitting a nearly uniform white ray to a designated length, the LED is a point light source for emitting a single colored ray. Accordingly, a great deal of research into emitting a white ray having uniform luminance to a designated length or designated dimensions is currently underway.
FIG. 1 is a schematic view of a conventional backlight source for an LCD using an LED. With reference to FIG. 1, the conventional backlight source 10 comprises LED packages 11, which are spaced from each other by designated intervals, and a light guide plate 12 provided with a designated pattern 121 formed thereon and separated from the LED packages 11 by a designated distance (d).
Each of the LED packages 11 of the above conventional backlight source 10 may be one package including RGB (Red, Green and Blue) LEDs, or is one of the above colored LEDs. In order to obtain light having uniform luminance, it is most preferable that a plurality of LED packages be densely arranged. However, the dense arrangement of the LED packages increases costs of the light source and the electric power consumption rate, thus being incapable of being practically employed.
Accordingly, as shown in FIG. 1, the LED packages 11 are spaced from each other by designated intervals. In this case, dark regions (D) are generated due to emitting angle of light emitted from the LED packages 11. In order to reduce the effect of the dark regions (D), the light guide plate 12 must be separated from the LED packages 11 by a sufficient distance (d). The distance (d) between the light guide plate 12 and the LED packages 11 increases the volume of the LCD, thus having a negative effect on the slim and lightweight trends.
The light guide plate 12 is necessary to obtain a uniform white ray by mixing red, green and blue rays generated from the LED packages 11. The light guide plate 12 is provided with the designated pattern 121 formed thereon, thereby extending an optical route in the restricted area and facilitating the mixing of the colored rays.
However, the light guide plate 12, separated from the LED packages 11 by the designated distance (d), increases the size of the LCD, and the intensity of light emitted from the LED packages 11 is concentrated on the central area, thus having a negative effect on the miniaturization of the LCD and deteriorating the uniformity of luminance.
Accordingly, there are required a novel LED package, which is usable as a light source for a backlight assembly of an LCD using an LED, and a light source, using the same, which provides a white ray having uniform luminance to a designated length and designated dimensions.